Safety and functional significance of Weissella cibaria and W. confusa 1 in food: a polyphasic approach 2

13 Weissella cibaria and Weissella confusa are controversial species of lactic acid bacteria (LAB) 14 found in food products. They are naturally present in many fermentation processes of vegetables 15 and cereals, with a positive implication for the quality of food. On the other hand, Weissella species 16 have been associated to possible human infections, and for this reason the strains of the species are 17 not yet used as starter cultures and are not included in Qualified Presumption of Safety status of 18 European Food Safety Authority (EFSA). An in-depth analysis of the physiological and genetic 19 characteristics of Weissella species could help to select suitable strains for possible practical 20 applications. A comparative genome analysis of 15 sequenced W. cibaria and five W. confusa 21 genomes available to date was carried out, in parallel with a polyphasic study of twelve strains of 22 W. cibaria and eight strains of W. confusa previously isolated from sourdough-like maize bran 23 fermentation. The comparative genomic analysis resulted in an absence of severe pathogenicity 24 factors. Although some putative virulence genes were found, these, for homology and function, 25 were present in other LAB species/strains, considered safe by EFSA and commonly used as 26 probiotics. The phenotypic tests carried out on our strains corroborated the genomic results. 27 Moreover, interesting functional and pro-technological traits were highlighted in the tested strains, 28 for both the species. 29